The objective of this Phase I SBIR application is the proof-of-principle for an innovative and reliable subdermal electroencephalogram (EEG) monitor. The EEG is the most widely-used monitor of brain function. Over a fifth of the population suffers from brain disorders that are diagnosed, treated, or investigated with the assistance of the EEG. The current tool for diagnosis of these disorders when the symptoms arise only during daily life is the ambulatory EEG system. This system is non-invasive and inexpensive, but alters the appearance and irritates the skin too severely for measurements to extend beyond a month. Recently released implanted neural- stimulation devices can, as a secondary function, record the EEG during daily life. However, these devices are too invasive and expensive for widespread use in treatment or monitoring. Physicians need an EEG monitor that continuously records for a decade or longer, provides exceptionally stable data collection, is unobtrusive, and is cost effective. To enter this untapped market, we propose to develop a novel reasonable-cost EEG monitor that can continuously and accurately record for many years without interfering with daily life. Physicians will be able to monitor the brain activity in a maner not available before and so the proposed device may shift current clinical practice. The proposed subdermal EEG Recorder is a flexible, 3 mm diameter cylinder. The length is 150 mm to 250 mm, depending on the number of monitoring locations. The exterior of the cylinder is predominantly medical- grade plastic except at 50 mm intervals there are 10 mm bands of biocompatible metal. The function of the bands is to sense the EEG signal. The proposed device is inserted between the scalp and skull through a small incision using well-known methods for placing similarly shaped objects such as catheters and leads. The long- term safety of a device in this location has been demonstrated by the leads used in deep brain stimulation. The proposed device is thin such that there is little or no change in the appearance of the patient. Once a day for less than half an hour, the patient rests a light-weight apparatus on the skin above the device to gather the EEG data from the implanted device and to charge the battery within the device. The size, location, and operation of the subdermal EEG recorder raise several implementation challenges. In this effort we intend to establish the technical feasibility by addressing these challenges through mechanical, electronic and biological studies. Successful completion of Phase I will lead to a Phase II study of surgery methods, mechanical reliability and electronic miniaturization with a Phase II goal of an animal-model demonstration of a pre-clinical prototype. PUBLIC HEALTH RELEVANCE: Many diseases of the brain create unusual small electrical activity that can be displayed in a graph known as the electroencephalogram (EEG). Doctors will discover better treatments for these diseases if the EEG of a patient is collected at all time for many years. This project is the first step in making a new inexpensive EEG recorder that does not interfere with the daily life of the patient.